将上面两等式相加,得 f(z)dz+4f(z)dz+f(z)dz AA +中f(z)dz+中f(z)dz+中f(z)dz=0 A'A BB BB 即∮f(2dz+5f(2)dz=0(31) 或中f(z)dz=f(z)dz (3.3.2)7 将上面两等式相加, 得 ( )d ( )d (3.3.2) ( )d ( )d 0 (3.3.1) ( )d ( )d ( )d 0 ( )d ( )d ( )d 1 1 1 ' ' ' '           = + = + + + = + + − − C C C C A A B B B B C C A A f z z f z z f z z f z z f z z f z z f z z f z z f z z f z z 或 即